The discovery that a small set of reprogramming factors (e.g. Oct4, Sox2, Klf4 and c-Myc) can induce the nuclear reprogramming of adult human cells to pluripotentiality, is a landmark development in regenerative medicine. Although human induced pluripotential stem cells (hiPSCs) promise a source of therapeutic cells, without the ethical issues or immune barriers of human embryonic stem cells (ESCs), the use of DNA-based methods for generating human induced pluripotential cells (hiPSCs) may introduce genetic or epigenetic errors during nuclear reprogramming. To overcome these safety concerns and to increase the efficiency of generating safe and effective iPSC, we will discover and refine new chemical entities (NCE) that induce reprogramming or enhance its efficiency. These new chemical entities include small molecules derived from a unique chemical library together with novel cell-permeant peptides designed for effective nuclear entry. We anticipate that NCE-based nuclear reprogramming will avoid concerns associated with DNA-based approaches such as DNA integration, as well as slow, inefficient and aberrant reprogramming. The knowledge that is generated, and the tools that are derived from that knowledge, will be useful for many stem cell biologists and investigators in regenerative medicine. Our specific aims are: 1) To develop and refine reagents and protocols for an efficient NCE-based strategy of generating hiPSCs. We will characterize the reprogramming efficiency using small molecules and peptides. This approach will provide for unbiased cell uptake (by comparison to DNA-based strategies), and more precise control over the dose, duration and timing of the reprogramming stimuli. 2) To characterize the safety and function of these hiPSCs. We will apply the genetic, epigenetic and mitochondrial analyses to characterize iPSCs generated by the NCE-based approach. Especially, we will focus on the differentiation of human iPSC to endothelial cells (EC) and apply the same rigorous genetic, epigenetic and mitochondrial analyses, as well as lineage-specific functional assays, to document the fidelity of hiPSC-EC to the expected phenotype. PUBLIC HEALTH RELEVANCE: This work will provide scientific insights, methodologies and reagents of utility for efficient nuclear reprogramming of human somatic cells into safe and effective hiPSCs for the entire regenerative medicine community.